Campbell Scientific HMP155A Temperature and Relative Humidity Probe - Manual (Page 20)

HMP155ATemperature and Relative Humidity Probe
When measuring the HMP155A with single-ended
measurements, the white and black leads must both be
connected to AG on the CR10(X) and CR500/CR510 or to
on the CR1000, CR5000, and CR23X. Doing otherwise
will connect the datalogger’s analog and power ground
planes to each other, which in some cases can cause offsets
on low-level analog measurements. To avoid 3 mA flowing
into analog ground, switch the sensor on/off for its own
measurement.
TABLE 7-1. Connections for Single-Ended Measurements
Color Wire Label CR10X
CR1000,
CR3000,
CR800,
CR5000,
CR23X
CR10, CR510,
CR500 21X, CR7 CR200(X)
Yellow Temp Signal Single-Ended
Input
Single-Ended
Input
Single-Ended
Input
Single-Ended
Input
Single-Ended
Input
Blue RH Signal Single-Ended
Input
Single-Ended
Input
Single-Ended
Input
Single-Ended
Input
Single-Ended
Input
White Signal
Reference
AG AG
Black Signal
Ground
AG AG
Clear Shield G G
Red Power
SW12V
SW12V SW12V 12V/SW12V* 12V/SW12V* SW Power
If using
SW12V,
jumper from
SW12V
Control
to Control Port
*On these dataloggers switched power is only available with the SW12V peripheral.
CAUTION
12